1. Field of the Invention
The present invention relates to a light input-adjustable window shade and, more particularly, to a light input-adjustable window shade that is adjustable for installation on spools and shade bodies of different lengths.
2. Description of the Related Art
A type of light input-adjustable window shade includes a supporting rod, a blind sheet or a shade body, and a weighting rod. The supporting rod is mounted to a top of a door or a window. An end of the shade body is fixed and wound around the supporting rod. The other end of the shade body is wound around the weighting rod and is coupled to the supporting rod. Thus, the shade body is folded relative to the weighting rod to form a dual-layer shade body structure permitting adjustment of the light input amount. An example of such a light input-adjustable window shade is disclosed in Japanese Patent Publication No. 1995-189573 and U.S. Pat. No. 7,267,156.
However, doors and windows have different sizes such that the user may have to purchase a light input-adjustable window shade of a corresponding size. To provide light input-adjustable window shades of different sizes, manufacturers have to provide supporting rods and weighting rods of different specifications for shade bodies of different sizes. Otherwise, the supporting rod or the weighting rod could be too long or too short for the shade body.
Accordingly, manufacturers must produce molds for production of supporting rods and weighting rods of different specifications for the purposes of providing light input-adjustable window shades of various sizes to be purchased by consumers, which greatly increase the production costs of the light input-adjustable window shades. Thus, a need exists for an improved light input-adjustable window shade to reduce the production costs for light input-adjustable window shades of various sizes and, hence, increase the market value of the light input-adjustable window shades.